Make your own DIY CD Spectroscope

What is a Spectroscope and How does it work?

A spectroscope is an instrument that produces a spectrum by the use of electromagnetic waves.

From earliest times, the rainbow has delighted and puzzled observers. People invented myths to explain the beautiful arc of multicoloured light that appeared after the rain. But a scientific answer to the puzzle of the rainbow did not come until 1666.

In that year, Sir Isaac Newton began investigating the problem of eliminating the colour fringes in telescope lenses. He decided that the trouble might lie in the character of light itself. So, he began to study how light formed colours.

He admitted a small beam of sunlight into a darkened room and passed it through a prism. The beam produced a band of colours just like the rainbow, ranging from red to yellow, green, and blue to violet. But when he passed the whole band of coloured lights through a prism in reverse position, the coloured band became white sunlight again.

From this, he reasoned that white light is really a mixture of coloured lights and that each colour is bent by a different amount when it passes through the prism. This difference in bending enables each colour to stand out separately and be visible. The band of coloured lights thus formed is called a spectrum. The rainbow is actually a spectrum formed by sunlight passing through raindrops.

Now that we know all about Spectroscopes, let’s make our own!

Got a kit in your hand? Let’s see what it consists of.


Step 1: Join parts 1 and 4 in part 2 as shown in the figure.

Step 2: Join parts 6 and 7 in the device as shown in the figure.

Step 3: Join part 5 on top of part 6 as shown in the figure.

Step 4: Join part 3 to the device wherein the rectangular cut is closer to part 5 as shown in the figure.

Step 5: Cut a piece of Compact disc (CD) in the shape as shown in the figure.

Step 6: Place the CD piece slowly in its slot, as shown in the figure, and the model is ready! Come on, Let’s see some SPECTRUM.

Experimenting with our new Spectroscope!

Insert the torchlight in the rectangular hole made in part 3 in the model in such a way that the white light strikes the CD.

View the spectrum of light from the other end, which has a small rectangular hole as shown in the figure.


fig. The wavelength of the Dispersed colours in nanometers

How many colours did you see the white light disperse into?

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